In the past, electrical components have been attached to printed circuit boards by various different techniques. One process, commonly used with axial-leaded components such as resistors, involves inserting the leads into holes in the board, and then clinching or staking the tips of the leads to the board to mechanically fasten the component to the board, after which the leads are connected to conductive printed-circuit areas or contact pads on a surface of the board as by soldering.
Another process, "reflow soldering," as discussed in more detail hereafter, is often used with multiple flat-leaded components, such as integrated circuits, wherein the component is physically held against a mounting surface of the board with the leads engaging contact pad areas on that surface. Either or both of the leads and pads are coated with solder, and the solder areas are subject to localized heating to melt the solder and make a bond.
An object of this invention is to provide a simple, low-cost fastening technique, wherein components of various different sizes and shapes may be mechanically fastened to the board at desired locations prior to any standard lead-attach step, by simple plastics-molding and forming techniques and structures. The process is especially useful to provide high-integrity mechanical connections, particularly in a solder-reflow process, where the component leads cannot be inserted into holes in the board, and also for use with molded thermoplastic substrates.